In washing machines for domestic use, the detergent is usually manually introduced into a chamber and flushed with water into the suds container after the wash cycle has started. The user must observe the dosage instructions for the particular detergent used, and take care to fill the correct amount into the chamber. To facilitate charging with detergent or other additives, such as fabric softeners, automatic dispensing systems in which a relatively large amount of detergent is stored in a supply container may be used. Once a wash cycle is started, the preset amount of detergent will then be added to the wash liquid, which eliminates the need for the user to ensure that the proper amount of detergent is filled in each time a wash cycle is carried out. Such dispensing systems are frequently used especially in industrial washing machines.
German document DE 33 02 893 C2 describes a washing machine having a dispensing system for liquid detergents, which is disposed separately from the washing machine. The dispensing system includes a separate housing in which are fixedly installed two supply containers for additives and which accommodates a control device and the metering pump. Water from the suds container is conveyed through hose connections to the dispensing system, where the additive is added to this water. The water/additive mixture is pumped into the washing machine through a second conduit in a region of the flush-in channel for fresh water supply. The dispensing system described therein is designed as a separate add-on unit, for which an additional, predetermined fixed place must be provided laterally adjacent to the washing machine. Connection of the dispensing system to the washing machine is via two hoses or pipes and a cable for power supply to the pump and for signal and/or data transmission. Space constraints make it difficult to access the containers for filling or cleaning.
Another dispensing system for liquid additives is described in DE 10 2005 050 083 A1. In that patent application, a supply container for liquid detergents is located outside the washing machine and connected thereto via a hose line. Disposed within the washing machine is the metering pump, which delivers the liquid or viscous detergent through a hose line to the lower region of the suds container. The metering pump is controlled by the washing machine controller which, based on the ON-time, determines the amount of detergent to be dispensed at any one time.
With these dispensing systems, the user can only use liquid or viscous detergents.
A dispensing system for powdered detergent is described in EP 0 297 371 B1 and WO 03/023120 A1. The washing powder is released from a supply container into a mixing chamber, from where it is delivered to the washing machine. An agitator having at least one rotating blade agitates the powder within the container, causing it to flow through an opening into the mixing chamber. Once the desired amount has been introduced into the mixing chamber, the mixing chamber is flushed with water, the outflowing detergent/water mixture being directed through a conduit to the washing machine. This dispensing system is not suitable for use with liquid detergent.
World patent application WO 2007/027779 A1 described a liquid additive dispensing system for a dishwasher. The liquid treating agent is dispensed or released into the treatment chamber by means of a pump. The dispensing system includes a base unit having a plurality of supply containers inserted therein. In order to dispense powdered treating agent, a different base unit is provided which has an additional water inlet, allowing the powder to be mixed with water and subsequently pumped to the dishwasher. This dispensing system has the disadvantage that it is only suitable for either liquid or powdered treating agent.